I claim the ornamental design for a plant protection device, substantially as shown.
FIG. 1 is a perspective view of a plant protection device according to the present invention.
FIG. 2 is a side elevation view of the plant protection device.
FIG. 3 is a top plan view of the plant protection device.
FIG. 4 is a perspective view of the second embodiment of the plant protection device according to the present invention.
FIG. 5 is a side elevation view of the second embodiment of the plant protection device; and,
FIG. 6 is a top plan view of the second embodiment of the plant protection device.
The plant protection device is shown with a symbolic break in the length of the legs. The appearance of any portion of the article between the break lines forms no part of the claimed design.